青岛能源所解析甘露聚糖功能研究取得新进展

纤维素合成类似酶CSLA2维持种子粘液质结构示意图

种子粘液质被认为是研究植物细胞壁多糖生物合成及其调控机制的理想模式体系。甘露聚糖作为细胞壁组分之一，与纤维素、半纤维素和果胶互相交联共同维持细胞壁的稳定性与完整性，并在植物生长发育中发挥着重要作用。

青岛能源所植物代谢工程团队于丽等研究人员以此为材料，阐明了纤维素合成类似酶CSLA2参与种子粘液质葡甘露聚糖的生物合成，并在维持种子粘液质结构方面发挥重要功能。该研究加深了人类对甘露聚糖在植物细胞壁形成过程中生理功能的认识，将为创制可高效转化利用的纤维生物质定向设计和遗传改良提供新思路。

该研究由青岛能源所研究员周功克主持完成，得到了国家自然科学基金、科技部项目等支持。

原文摘要：

CSLA2, a Glucomannan Synthase, is Involved in Maintaining Adherent Mucilage Structure in Arabidopsis Seed

Li Yu, Dachuan Shi, Junling Li, Yingzhen Kong, Yanchong Yu, Guohua Chai, Ruibo Hu, Juan Wang, Michael G. Hahn and Gongke Zhou

Mannans are hemicellulosic polysaccharides that are considered to have both structural and storage functions in the Plant Cell wall. However, it is not yet known how mannans function in Arabidopsis seed mucilage. In this study, CELLULOSE SYNTHASE-LIKE A2 (CSLA2) expression was observed in several seed tissues, including the epidermal cells of developing seed coats. Disruption of CSLA2 resulted in thinner adherent mucilage halos, although the total amount of the adherent mucilage did not change compared to wild type. This suggested that the adherent mucilage in the mutant was more compact compared to that of the wild type. In accordance with the role of CSLA2 in glucomannan synthesis, csla2-1 mucilage contained 30% less mannosyl and glucosyl content than did the wild-type. No appreciable changes in the composition, structure, or macromolecular properties were observed for non-mannan polysaccharides in mutant mucilage. Biochemical analysis revealed that cellulose crystallinity was substantially reduced in csla2-1 mucilage; this was supported by the removal of most mucilage cellulose through treatment of csla2-1 seeds with endo-β-glucanase. Mutation in CSLA2 also resulted in altered spatial distribution of cellulose and an absence of birefringent cellulose microfibrils within the adherent mucilage. As with the observed changes in crystalline cellulose, the spatial distribution of pectin was also modified in csla2-1 mucilage. Taken together, our results demonstrate that glucomannans synthesized by CSLA2 are involved in modulating the structure of adherent mucilage, potentially through altering cellulose organization and crystallization.

标签: 甘露聚糖 种子粘液质 植物细胞壁多糖

作者：中科院 点击：次

;